Caliper type brake structure

ABSTRACT

The brake unit as described herein is a caliper disc brake to be mounted in relationship to a driving disc which may be fixed or slideably mounted to a shaft or other driving means, which driving means is capable of imparting rotation to the disc. The caliper disc brake assembly is provided for stopping the rotation of the driving disc by utilizing externally applied actuating or energizing force and automatically applied internal actuating or energizing force.

United States Patent Hahn [ 51 Mar. 28, 1972 [54] CALIPER TYPE BRAKESTRUCTURE [72] Inventor: Emil H. Hahn, St. Joseph, Mich,

[73] Assignee: Lambert Brake Corporation, St. Joseph,

Mich.

[22] Filed: May 4, 1970 [21] Appl. No.: 34,393

[52] US. Cl ..l88/72.2, 188/727, 188/729 [51] Int. Cl ..Fl6d 55/46 [58]Field of Search ..188/72.2, 72.7, 72.9

[56] References Cited UNITED STATES PATENTS 2,655,229 10/1953 Eksergian..188/72.2 3,211,261 10/1965 Chouings.... ..l88/72.9 3,314,506 4/1967Belart et al. ..188/l06 F X 3,463,274 8/1969 Hollnagel et a] ..l88/72.7

FOREIGN PATENTS OR APPLICATIONS 1,489,537 6/1967 France ..188/72.21,005,382 9/1965 Great Britain ..l88/72.2

Primary Examiner-George E. A. Halvosa Attorney-Olson, Trexler, Wolters &Bushnell [5 7] ABSTRACT The brake unit as described herein is a caliperdisc brake to be mounted in relationship to a driving disc which may befixed or slideably mounted to a shaft or other driving means, whichdriving means is capable of imparting rotation to the disc. The caliperdisc brake assembly is provided for stopping the rotation of the drivingdisc by utilizing externally applied actuating or energizing force andautomatically applied internal actuating or energizing force.

7 Claims, 10 Drawing Figures PATENTEDMAREBIQYZ 3.651 ,897

I sum 3 OF 3 CALIPER TYPE BRAKE STRUCTURE SUMMARY OF THE INVENTION Thepresent invention relates to a novel friction device, and morespecifically to a novel brake structure.

OBJECTS AND BRIEF DESCRIPTION OF THE DRAWINGS An important object of thepresent invention is to provide a novel brake assembly adapted toembrace and engage areas of a rotary member to be controlled, which unitmay be selectively actuated mechanically or with fluid under pressure.

A more specific object of the present invention is to provide a novelcaliper type brake assembly which may be actuated with hydraulic ormechanical means.

A further specific object of the present invention is to provide a novelcaliper type brake assembly of the abovedescribed type which in additionto having hydraulic or mechanical actuating means, includes aself-actuating mechanism.

Yet another object of the present invention is to provide a novelcaliper type brake assembly of the above-described type which isautomatically repositioned in a non-actuating position when thehydraulic or mechanical actuating means is released.

A further object of the present invention is to provide a novel caliperbrake assembly of the above-described type which is of relativelysimple, economical and efficient construction.

Other objects and advantages of the present invention will becomeapparent from the following description of the accompanying drawingswherein:

FIG. 1 is a front sectional view showing one embodiment of the caliperbrake assembly incorporating the features of the present inventionassociated'with a rotatable member to be controlled;

FIG. 2 is a fragmentary sectional view taken generally along line 22 ofFIG. 1 and including a mechanical external actuating mechanism;

FIG. 3 is a further fragmentary sectional view taken along lines 3-3 ofFIG. 1;

FIG. 4 is a still further fragmentary sectional view taken along lines22 of FIG. 1 and including a hydraulic external actuating mechanism; 1

FIG. 5 is a side view of caliper caliper brake assembly taken alonglines 55 of FIG. 1;

FIG. 6 is a fragmentary sectional view taken along lines 6 6 of FIG. 1;

FIG. 7 is a partial front view showing a second embodiment of thecaliper brake assembly incorporating features of the present inventionassociated with a rotatable member to be controlled;

FIG. 8 is a cross-sectional view taken along lines 8-8 of FIG. 7 andincluding a mechanical external actuating mechanism;

FIG. 9 is a partial front view of the caliper brake assembly including ahydraulic external actuating mechanism of FIG. 7; and,

FIG. 10 is a cross-sectional view taken along lines 10-10 of FIG. 9.

DETAILED DESCRIPTION Referring to the drawings and specifically FIGS. 1to 6', wherein like parts are designated by the same numerals throughoutthe figures, the caliper brake assembly 10 incorporating features of thepresent invention is shown in assembled relationship with a rotarymember or driving disc 12. The driving disc 12 is fixed on a rotatableshaft 14 which may, for example, be an axle of a small vehicle, truck orthe like, the rotatable shaft 14 imparting rotation to the driving disc12. The rotary member or driving disc 12 and the shaft 14 might also beparts of various pieces of machinery as well as parts of a vehicle. Inother words, the caliper brake assembly may be adapted for stopping anydesired rotatable member.

The driving disc 12, in addition to being fixed to the rotatable shaft14 for rotation therewith, may be either rigidly held in place orslideable along the longitudinal axis of the shaft. In the latter case,the driving disc 12 and rotatable shaft 14 would include a plurality ofcomplementary splines 16 and 18 respectively which cooperate with eachother for allowing the driving disc to slide axially along the shaft. Ina caliper brake assembly of the type described herein, if the drivingdisc 12 is rigidly fixed to the rotatable shaft 14, the caliper brakeassembly must be slideably mounted in a manner and for reasons describedhereinafter. On the other hand, if the driving disc is slideably mountedto its associated rotatable shaft the caliper brake assembly must berigidly held in place.

The caliper brake assembly 10 comprises a mounting bracket 20 forsuitably mounting the assembly adjacent a portion of the periphery ofdriving disc 12 as best seen in FIG. 1. The caliper brake assembly canbe slideably mounted on pins or bars (not shown) through bores or holes22 of mounting bracket 20, the assembly being slideable in a directiontransverse to the driving disc 12 as best seen in FIGS. 1 and 2. Thiswould be necessary, as stated above, if the driving disc 12 were rigidlyfixed to the rotatable shaft 14. On the other hand, if the driving disc12 is slideably mounted to rotatable shaft 14, the mounting bracket 20and therefore the caliper brake assembly 10 can be bolted to a portionof the associated machine by means of these same holes or bores.

A fixed actuating plate or end plate 24 is positioned on one side of thedriving disc 12 and in confronting relationship therewith, the fixedactuating plate extending along a portion of the periphery of drivingdisc 12. The fixed actuating plate is rigidly mounted on one end thereofto one side of the mounting bracket 20 by a common bolt 26, the mountingbracket laterally spacing the fixed actuating plate a predetermineddistance from the driving disc 12 as seen in FIG. 2.

A secondary plate 28 is positioned on the opposite side of driving disc12 and in direct alignment with the fixed Actuating plate on end plate24. The secondary plate is mounted on one end thereof to the oppositeside of mounting bracket 20 by common bolts 26 which extend entirelythrough the mounting bracket as seen in FIG. 2. With the secondary plate28 and the end plate 24 mounted to the mounting bracket 20 in the mannerjust described, the plates are rigidly held a predetermined distanceapart by the mounting bracket.

A movable actuating plate or primary plate 30 is positioned directlybetween the driving disc 12 and secondary plate 28, the primary platebeing held in this position solely by a self-actuating or energizingmechanism to be described hereinafter. The primary plate 30 ispositioned for movement in a direction transverse to the driving disc 12so that a frictional lining located thereon can engage or come incontact with the driving disc. Attached to the inner surface of primaryactuating plate 30 by some conventional method, bonding, riveting,molding or the like, is one of a pair of opposed frictional linings 32and 34 respectively, its complementary lining being attached in the samemanner to fixed actuator plate or end plate 24. As seen in FIG. 2, thefrictional linings 32 and 34 are in non-contacting relationship with thedriving disc 12. As will be described hereinafter, when the caliperbrake assembly is actuated or energized causing the primary plate tomove toward the driving disc, frictional lining 32 engages the discwhich ultimately causes both frictional linings to engage the disc andthereby stop its rotation.

The caliper brake assembly 10 can be readily adapted for externalactuation or energization by either a mechanical mechanism 36 shown inFIG. 2 or a hydraulic mechanism 38 shown in FIG. 4. A solid hard ball 40made of steel or the like is movably held within a bore or hole 42 inthe secondary plate 28. The ball is provided for transmitting an appliedforce to the primary plate 30 so as to cause the primary plate to movetowards the driving disc 12, the frictional lining 32 thereby initiallyengaging the driving disc. Upon engagement with the rotating drivingdisc 12, the primary plate 30 and friction lining 32 begin to rotate inthe same direction. 'As will be described in detail hereinafter, uponthis initial movement of the primary plate, the self-actuating mechanismto be described below causes the friction lining 32 to further engagethe driving disc 12 and in addition causes the friction lining 34 toengage the opposite side of the driving disc. With both friction liningsappropriately engaged with the driving disc, the driving disc is causedto stop which in turn causes the axial rotation of rotating shaft 14 tostop.

Turning specifically to FIG. 2, the external mechanical actuating deviceor mechanism 36 is shown and includes a triangular back up or leverplate 44 which is positioned in confronting relationship with andlaterally spaced from the secondary plate 28. The lever plate is mountedto the secondary plate by a bolt 46 and previously described bolts 26.The bolt 46 passes through the lower vertex of the triangular leverplate and thereafter through one of three spacers 48 and into thesecondary plate as seen in FIGS. 1 and 2. The previously described bolts26 in addition to extending through end plate 24, mounting bracket 20,and secondary plate 28 extend through spacers 48 and lever plate 44 atthe upper vertices of the lever plate as seen in FIG. 1.

The external mechanical actuating device 36 further includes alongitudinally extending mechanical lever 50 which contains asubstantial conical or generated ball seat 52 at its lower end, the ballseat being shaped so as to co-operate with external actuating ball 40 ina manner to be described hereinafter. The mechanical lever is pivotablymounted to and between the lever plate 44 and secondary plate 28 by aspacer pin 54 which can best be seen in FIG. 1. The ball seat 52 ispositioned adjacent to and faces the hole or bore 42 in secondary plate28 and aids in supporting external actuating ball 40, the outwardlyextending external surface of the ball seat resting adjacent the back upor lever plate 44 as seen in FIG. 2. The other end of mechanical lever50 extends outward from between the lever plate and secondary plate sothat a manually applied force can be exerted thereto.

operationally, a lateral force is applied to the free or outwardlyextending end of mechanical lever 50, that is the free end of lever 50is pulled either to the left or the right as viewed in FIG. 1 which inturn causes the lever to pivot about the longitudinal axis of spacer pin54. As the mechanical lever pivots, the ramp of ball seat 52 rides up onexternal actuating ball 40 and through it translates the laterallyapplied force to a force perpendicular to primary plate 30. Reaction tothis perpendicular or normal force is taken by the contact of the backof the ball seat or lever plate 44. As stated above, this perpendicularor normal force applied to the primary actuating plate 30 causes theplate to move towards the driving disc 12 so that friction lining 32 mayengage the driving disc.

Turning now to FIG. 4, the external hydraulic actuating device ormechanism is shown and may easily replace the above described mechanicalactuating device or mechanism 36. The hydraulic actuating devicecomprises a hydraulic actuated piston and cylinder assembly including anopen ended cylinder 56 which serves as a spacer and which has one openend positioned in contacting relationship with secondary plate 28 andentirely encompasses bore or hole 42. The piston and the cylinderassembly further includes a piston 58 which is mounted for axialmovement within cylinder 56, one end of the piston aiding in supportingexternal actuating ball 40 as seen in FIG. 4. A cylinder cap 60 ismounted to the otherwise free end of cylinder 56 and includes an openingtherein which provides for connection to a conventional hydraulicsource, only the hydraulic line 62 being shown. A pair of O-rings 64 areprovided for sealing the hydraulic fluid between the piston 58 andcylinder cap 60. The mechanical actuating device or mechanism is boltedto the secondary plate 28 by three radially spaced screws 66 (only twobeing shown) which extend through the cylinder cap 60 and are threadedinto co-operating holes or bores in the secondary plate. In this casethe above described bolts 26 do not aid in supporting the hydraulicactuating device and therefore may be shorter in length than thosedescribed with respect to FIG. 2.

operationally, the hydraulic actuating device or mechanism provides thesame ultimate function as that of the mechanical actuating mechanism.However, instead of using a manually applied lateral force as describedabove, the hydraulic actuating device or mechanism uses a hydraulicallyapplied perpendicular or normal force for driving the external actuatingball 40 into the primary plate 30.

Referring now specifically to FIGS. 3, 6 and 9, the previously mentionedself-energizing mechanism will be described in detail. Theself-energizing mechanism includes a plurality of hard balls 68 whichmay be made of steel or the like. The embodiments herein disclosedutilize two such balls. However, it is to be understood that anyreasonable number of balls may be provided. Each ball 68 is seated orpositioned within a pair of complementary substantially conically shapedor generated depressions 70 and 72 in the secondary plate 28 and primaryplate 30 respectively. A spring or springs (not shown) may be providedbetween the secondary plate 28 and primary plate 30 in order to keep theballs 68 positioned in the bottom of their respective depressions whenthe brake is not actuated. It is to be noted that the primary plate 30and attached frictional lining 32 are supported entirely by the balls 68on one side thereof and the driving disc 12 on the other side thereof,the primary plate being entirely free of the remaining structure. Thatis to say, if the balls 68 were removed the primary plate would dropdownward as can readily be seen in FIG. 2. Being so supported, theprimary plate 30 is easily movable towards and away from the drivingdisc 12 in a manner and for reasons described below.

Turning now to the operation of the self-energizingmechanism, it isfirstly to be assumed that the driving disc 12 is mounted for slideablemovement along the rotating shaft 14 and that the mounting bracket 20 isfixedly mounted in the manner described above. Upon applying aperpendicular or normal force on external actuating ball 40 in themanner described above, the friction lining 32 of primary plate 30 ismoved into contact with one side of driving disc 12 which in turn ismoved or slid so that its other side is in contacting relationship withthe friction lining 34 of end plate 24, the running clearances 74 and 76on each side of the rotating or driving disc 12 being absorbed by thesemovements. Friction lining 32 of the primary plate upon coming intofrictional contact with the rotating driving disc 12 causes the primaryplate to rotate in the same direction as that of the disc. This is quitepossible since, as stated above, the primary plate is only supported bythe balls 68 and the rotating or driving disc 12. As the primary platerotates along with the driving disc 12, each ball 68 will tend to move,in a relative manner, up the opposed sides of its associated depressions70 and 72 resulting in opposing perpendicular or normal forces beingapplied to the secondary plate. 28 and primary plate 30 respectively.These opposing forces create a spreading action between the secondaryplate and the primary plate. However, since the secondary is rigidlyfixed due to the mounting bracket 20 being rigidly fixed, this spreadingaction causes the friction lining 32 of primary plate 30 to furtherengage one side of the driving disc. As the primary plate continues torotate along with the driving disc, the balls 68 move further up theopposed sides of their respective depressions which in turn results in agreater spreading action. Ultimately, the driving disc will besufficiently squeezed or clamped by the friction linings 32 and 34causing it to cease rotating and thereby stopping the rotating shaft 14.

Operation of the self-energizing mechanism, assuming a fixed drivingdisc 12 and a floating" mounting bracket 20, is substantially the sameas described above except that after the primary plate 30 moves up toabsorb running clearance 74, the entire brake assembly floating on pins(not shown) in holes 22 of the mounting bracket moves to the left (asviewed in FIG. 2) until running clearance 76 is displaced by lining 34of fixed end plate 24. With both running clearances absorbed, brakingaction follows in the same manner as described above.

Turning specifically to FIGS. 5 and 6, the caliper brake assembly 10 isshown to include two C-shaped" calipers or clamps 80 which are laterallyspaced and mounted to end plate 24 and secondary plate 28 in a manner tobe described hereinafter. It is to be understood that while only twocalipers are shown, the invention contemplates any reasonable number oflaterally spaced calipers.

Each caliper 80 comprises two laterally spaced side portions 82integrally connected at their respective ends by a web or upper portion84. The otherwise free ends of side portions 82 include integrallyconnected and inwardly extending bottom portions 86. As seen in FIG. 5,the lower surface of web 84 of each caliper 80 is mounted withinco-operating aligned slots 88 and 90 of the secondary plate 28 and theend plate 24 respectively, the inner surface of each side portion 82being positioned in contacting relationship with the outer surface ofthe secondary plate and end plate respectively. The upper surfaces ofinwardly extending portions 86 are mounted within aligned and laterallyspaced slots 92 and 94 in the lower end of the secondary plate and endplate.

As described above, the end plate 24 and secondary plate 28 are held inspaced relationship by the mounting bracket 20 and are held together bybolts 26. The calipers or clamps 80 provide rigidity and resist thespreading action imparted to the secondary plate and end plate by theabove described opposing forces of balls 68 during self-actuation. Thatis, all the reaction to the perpendicular or normal force is takenthrough the calipers and none is transmitted to the bolts 26. Thisprovides for not only a rigid brake assembly but also a more reliablebrake assembly.

Turning to FIGS. 7 through 10, a modified caliper brake assembly 100 isshown and is identical in many respects to the caliper brake assemblydescribed above. Therefore, those features which are identical in bothembodiments will be designated by the same numerals and will not bediscussed except where necessary. It will suffice merely to state thatembodiment 100, like embodiment 10, may be provided with either anexternal mechanical actuating device or mechanism 36 (FIGS. 7 and 8) oran external hydraulic actuating device or mechanism 38 (FIGS. 9 and 10).g

The main difference between the caliper brake assembly 100 and thecaliper brake assembly 10 resides in a spring mechanism 102 which isprovided by the assembly 100 for returning the primary plate 30 to itsnon-operating position after actuation or energization of the brakeassembly ceases. That is, the spring mechanism repositions balls 68 intothe bottom of their respective complementary depressions 70 and 72.

The spring mechanism 102, which is substantially U-shaped and made froma highly resilient material, comprises two laterally spaced anddownwardly extending side portions 104 and 106 integrally joined atrespective upper ends by a substantially curved web or upper portion108. The free end of side portion 106 includes an upwardly extending andintegrally connected bight 110 for aiding in supporting the springmechanism in the manner described hereinafter.

The friction lining 32 of primary plate 30 and the friction lining 34 ofend plate 24 include aligned vertically extending slots (not shown)which extend the entire length of their respective plates and are ofapproximately the same width as the spring mechanism 102. The sideportions 104 and 106 of the spring mechanism are snugly mounted withinrespective slots of friction linings 32 and 34 so that the web or topportion 108 extends around and above the top of driving disc 12 as seenin FIGS. 8 and 10. The bight 110 is clamped around the bottom of endplate 24 for aiding in supporting the spring mechanism 102. The sideportion 104 is spring biased in its vertically extending position asseen in FIGS. 8 and 10, that is in the caliper brake assemblynon-operating position. Additionally, the side portion 104 and sideportion 106 are spring biased away from each other so as to force theirrespective friction lining away from the sides of driving disc 12. Thisin turn insures positive running clearances between each side of thedriving disc 12 and the friction linings 32 and 34 respectively whereasthe caliper brake assembly 10 of FIGS. 1 to 4, without a springmechanism 102, depends upon the floating, or unrestricted movement, ofthe primary plate 30 for clearance.

As stated above, the spring mechanism 102 is used primarily forreturning the primary plate 30 to its non-operating position after thebrake assembly has stopped the driving disc 12 and rotating shaft 14. Inoperation the frictional contact of friction lining 32, attached toprimary plate 30, with driving disc 12 imparts a lateral or rotationalmovement to the primary plate. As viewed in FlGS. 8 and 10, thedirection of this lateral or rotational movement is either into or outof the drawing depending upon the driving discs direction of rotation.As the primary plate moves along with the driving disc, it causes theside portion 104 of spring mechanism 102 to be driven therewith, theside portion being moved from its biased position. Upon release of thebraking action, the biased side portion returns to its biased positionand therefore returns the primary plate 30 to its original non-operatingposition. This in turn, repositions the balls 68 into the bottom oftheir respective complementary depressions and the brake assembly isagain ready for actuation or energization.

The only other noted variation in the caliper brake assembly as comparedto the assembly 10 resides in the mechanical lever 112. This lever is asimplified version of mechanical lever 50 in assembly 10, the mechanicallever 112 utilizing a V-shaped groove 114 rather than a conically shapedor generated ball seat.

With both embodiments of the caliper brake assembly being described, itis to be noted that all components are simple in structure. That is, allthe components making up either embodiment can be made by simplestamping or tubing methods. Machine operations are limited to threadingholes and drill pointing the ball ramps. This in turn provides for aneconomical brake assembly.

While particular embodiments of the invention have been shown, it shouldbe understood, of course, that the invention is not limited theretosince many modifications may be made. It is, therefore, contemplated tocover by the present application any such modifications as fall withinthe true spirit and scope of the appended claims.

The invention is claimed as follows:

1. A caliper brake assembly for retarding the rotation of a disc mountedon a rotating shaft comprising mounting means for mounting said assemblyadjacent a peripheral portion of the disc and including caliper meansfor embracing the disc, first and second plate means respectivelypositioned on opposite sides of said disc and supported by said mountingmeans for engagement with said disc during energization of saidassembly, said first plate means being supported for limited rotativemovement with said disc, secondary plate means fixed to said mountingmeans and positioned adjacent to and in COnfronting relationship withsaid first plate means, said secondary plate means including bore meanstherethrough having a wall, a ball movable axially within and retainedby said bore means and engaging said wall and said first plate means,force application means axially spaced from said bore and engaging saidball for axially shifting said ball and initially moving said platemeans into engagement with said disc whereby said disc imparts limitedrotational movement to said first plate means, automatic brake actuatingmeans comprising opposing cam surfaces on said first plate means andsaid secondary plate means and ball means between and engaging saidsurfaces and responsive to said limited rotational movement for forcingsaid first plate means into further engagement with said disc, and saidcaliper means being connected to and preventing spreading of saidsecondary plate means and said second plate means.

2. A caliper brake assembly according to claim 1 wherein said forceapplication means includes longitudinally extending mechanical levermeans engaging said ball, said lever means being manually movable forforcing said ball against said first plate means.

3. A caliper brake assembly according to claim 1 wherein said forceapplication means includes hydraulic means for hydraulically forcingsaid ball against said first plate means.

4. A caliper brake assembly according to claim 1 wherein said mountingmeans is mounted for movement transversely with the sides of said discand said disc is rigidly fixed to said rotating shaft, said mountingmeans being moved by said automatic brake actuating means for movingsaid second plate means into engagement with said disc during brakeenergization.

5. A caliper brake assembly according to claim 1 wherein said mountingmeans is rigidly mounted adjacent a predetermined peripheral portion ofsaid disc and said disc is slideably mounted to said rotating shaft formovement along the rotating shaft, said external brake actuating meansmoving said disc into engagement with said rotating disc along with saidfirst plate means.

6. A caliper brake assembly according to claim 1 including springbiasing means operatively connected to said first plate means for springbiasing said first plate means in a de-energized position, said springbiasing means moving with said first plate means during initial brakeenergization and automatically returning said first plate means to itsdeenergized position when the rotation of said disc ceases.

7. A caliper brake assembly according to claim 6 wherein said springbiasing means is operatively connected to said second plate means forbiasing said first and second plate means away from said disc duringbrake de-energization whereby adequate clearances are maintained forrotation of said disc along with said rotating shaft.

1. A caliper brake assembly for retarding the rotation of a disc mountedon a rotating shaft comprising mounting means for mounting said assemblyadjacent a peripheral portion of the disc and including caliper meansfor embracing the disc, first and second plate means respectivelypositioned on opposite sides of said disc and supported by said mountingmeans for engagement with said disc during energization of saidassembly, said first plate means being supported for limited rotativemovement with said disc, secondary plate means fixed to said mountingmeans and positioned adjacent to and in confronting relationship withsaid first plate means, said secondary plate means including bore meanstherethrough having a wall, a ball movable axially within and retainedby said bore means and engaging said wall and said first plate means,force application means axially spaced from said bore and engaging saidball for axially shifting said ball and initially moving said platemeans into engagement with said disc whereby said disc imparts limitedrotational movement to said first plate means, automatic brake actuatingmeans comprising opposing cam surfaces on said first plate means andsaid secondary plate means and ball means between and engaging saidsurfaces and responsive to said limited rotational movement for forcingsaid first plate means into further engagement with said disc, and saidcaliper means being connected to and preventing spreading of saidsecondary plate means and said second plate means.
 2. A caliper brakeassembly according to claim 1 wherein said force application meansincludes longitudinally extending mechanical lever means engaging saidball, said lever means being manually movable for forcing said ballagainst said first plate means.
 3. A caliper brake assembly according toclaim 1 wherein said force application means includes hydraulic meansfor hydraulically forcing said ball against said first plate means.
 4. Acaliper brake assembly according to claim 1 wherein said mounting meansis mounted for movement transversely with the sides of said disc andsaid disc is rigidly fixed to said rotating shaft, said mounting meansbeing moved by said automatic brake actuating means for moving saidsecond plate means into engagement with said disc during brakeenergization.
 5. A caliper brake assembly according to claim 1 whereinsaid mounting means is rigidly mounted adjacent a predeterminedperipheral portion of said disc and said disc is slideably mounted tosaid rotating shaft for movement along the rotating shaft, said externalbrake actuating means moving said disc into engagement with saidrotating disc along with said first plate means.
 6. A caliper brakeassembly according to claim 1 including spring biasing means operativelyconnected to said first plate means for spring biasing said first platemeans in a de-energized position, said spring biasing means moving withsaid first plate means during initial brake energization andautomatically returning said first plate means to its deenergizedposition when the rotation of said disc ceases.
 7. A caliper brakeassembly according to claim 6 wherein said spring biasing means isoperatively connected to said second plate means for biasing said firstand second plate means away from said disc during brake de-energizationwhereby adequate clearances are maintained for rotation of said discalong with said rotating shaft.